Study on the thermal behaviour of spontaneous combustion of open-pit minerals.

To study thermal behaviour during spontaneous combustion of an open-pit coal mine, mixed slag (coal, oil shale, and coal gangue) was taken as the research object. Laser thermal conductivity analyser and differential scanning calorimetry were used to test thermophysical parameters and heat release characteristics of the minerals. The parameters can be employed to calculate the apparent activation energy using the Arrhenius equation and evaluate the thermal behaviour of open-pit mixed slag. The results indicate that thermophysical parameters have stage characteristics. Thermal diffusivity and thermal conductivity of minerals, especially mixed slag, have a strong correlation with temperature. Heat flow of minerals exhibits five characteristic stages, and heat flow of the samples is consistent with the change in heating rate. During the heating process, thermal diffusivity and heat flow of the mixed slag are between those of a single mineral. Except for the mixed slag at 15 and 20 °C/min, the initial exothermic temperature of the other samples is mainly concentrated at 50-80 °C. Thermal energy release of the sample is mainly concentrated in the accelerated exothermic stage and rapid exothermic stage. Thermal energy release of mixed slag in rapid exothermic stage is always greater than that in accelerated exothermic stage, and the proportion of thermal energy release in these two stages exceeds 98 %. The apparent activation energy during the accelerated exothermic stage is lower, making it easier to release heat, and rapid exothermic stage is relatively high, which can readily lead to heat accumulation. Thermal analysis reveals that the thermal behaviour of mixed slag is significantly different from that of a single mineral. Its unique exothermic characteristics can provide a more accurate theoretical basis for the prevention and control of environmental pollution caused by slag spontaneous combustion.

Utility, benefits, and risks of newborn genetic screening carrier reports for families.

Background: Newborn genetic screening (NBGS) based on next-generation sequencing offers enhanced disease detection and better detection rates than traditional newborn screening. However, challenges remain, especially around reporting the NBGS carrier results. Therefore, we aimed to investigate the NBGS carrier parents' views on NBGS and NBGS reports in China. Methods: We distributed a survey querying demographic information, knowledge and perceptions of NBGS, the impact of NBGS on a total of 2930 parents, and their decision-making to parents of newborns reported as carriers in NBGS in Nanjing, China in 2022. Results: The average age of the survey respondents was 30.7 years (standard deviation = 3.6). Most (68.38%) felt informed about NBGS, especially women, the highly educated, and high earners. Nearly all (98.74%) saw NBGS as crucial for early disease detection, with 73.18% believing it positively impacts their future. However, 19.16% felt it might cause anxiety, especially among the less educated. Concerns included potential discrimination due to exposed genetic data and strained family ties. Many suggested NBGS coverage by medical insurance to ease financial burdens. Conclusions: Through our study, we gained insights into parents' perspectives and concerns regarding the NBGS carrier result reporting, thus providing relevant information for further refinement and clinical promotion of the NBGS project.

Unveiling the potential of mitochondrial dynamics as a therapeutic strategy for acute kidney injury.

Acute Kidney Injury (AKI), a critical clinical syndrome, has been strongly linked to mitochondrial malfunction. Mitochondria, vital cellular organelles, play a key role in regulating cellular energy metabolism and ensuring cell survival. Impaired mitochondrial function in AKI leads to decreased energy generation, elevated oxidative stress, and the initiation of inflammatory cascades, resulting in renal tissue damage and functional impairment. Therefore, mitochondria have gained significant research attention as a potential therapeutic target for AKI. Mitochondrial dynamics, which encompass the adaptive shifts of mitochondria within cellular environments, exert significant influence on mitochondrial function. Modulating these dynamics, such as promoting mitochondrial fusion and inhibiting mitochondrial division, offers opportunities to mitigate renal injury in AKI. Consequently, elucidating the mechanisms underlying mitochondrial dynamics has gained considerable importance, providing valuable insights into mitochondrial regulation and facilitating the development of innovative therapeutic approaches for AKI. This comprehensive review aims to highlight the latest advancements in mitochondrial dynamics research, provide an exhaustive analysis of existing studies investigating the relationship between mitochondrial dynamics and acute injury, and shed light on their implications for AKI. The ultimate goal is to advance the development of more effective therapeutic interventions for managing AKI.

Sequencing and analysis of the complete mitochondrial genome of Eothenomys eleusis Thomas 1911 from China and its phylogenetic analysis.

The complete mitogenome sequence of Eothenomys eleusis Thomas 1911 was determined using PCR. A circular double-stranded structure makes up the mitochondrial genome of E. eleusis. The complete length of the mitochondrial genome is 16,419 bp. The mitochondrial genome of E. eleusis included 13 protein-coding genes, 1 control region, 22 tRNA genes, 2 rRNA genes and 1 origin of L strand replication. The total base composition of E. eleusis mitochondrial genome was A (32.6%), T (26.3%), G (13.6%) and C (27.5%). We found significant A-T skew in base composition, especially in control regions and protein-coding genes. E. eleusis was supported by bootstrap values of 100%. This study verifies the evolutionary status of E. eleusis in Myodini tribe of Cricetidae at the molecular level. The mitochondrial genome would be a significant supplement for the E. eleusis genetic background.

Prevalence of myopia among children and adolescents in Inner Mongolia Autonomous Region from 2019 to 2021 / 中国学校卫生

Objective@#To analyze the prevalence and trend of myopia among children and adolescents in Inner Mongolia from 2019 to 2021，so as to provide a reference for making scientific and effective prevention and controlling measures of myopia.@*Methods@#By using the stratified random cluster sampling method, 555 093 children and adolescents were selected from 12 professional institutions in league cities of the whole region for remote vision examination and refractive examination. The refraction test was carried out under the condition of non-Ciliary muscle paralysis using a desktop automatic computer optometer. Chi-squared test and multivariate Logistic regression were used to analyze the myopia status of children and adolescents and its influencing factors.@*Results@#From 2019 to 2021, the myopia rate of children and adolescents was 53.30%, 58.65% and 54.82%, respectively, the difference was statistically significant ( χ 2=991.70, P <0.01). The overall female myopia rate(58.82%) was higher than that of male (51.52%), and the differece was statistical significant ( χ 2=3 295.66, P <0.05). The myopia rates of boys and girls by year were 49.44% and 57.30%, 54.76% and 62.60%, 51.23% and 57.62%, respectively, and the differences were statistically significant ( χ 2=1 197.02, 922.31, 1 172.09, P <0.01). The overall myopia rate of urban students (59.42%) was higher than that of suburban counties (53.61%), and the difference was statistically significant ( χ 2=1 565.03, P <0.05). The myopia rates of children and adolescentss in urban and suburban counties were 59.20% and 50.79%, 60.26% and 57.88%, 58.95% and 53.36%, and the differences were statistically significant ( χ 2=1 150.80, 74.10, 529.25, P <0.01). The children and adolescents of learning stages were of statistical significance ( χ 2=92 402.39, P <0.05), and the overall myopia rate of senior school students was the highest, accounting for 83.57%. The difference of overall myopia rates of different age groups was of statistical significance ( χ 2=121 881.67, P <0.05), and the students in age group of 17 ranked the first (83.32%), those in age group of 5 ranked the last(15.52%).@*Conclusion@#From 2019 to 2021, the myopia rate of children and adolescents in the Inner Mongolia Autonomous Region increase first and then decrease, and the myopia rate in 2020 and 2021 is higher than that in 2019. The high incidence and low age of myopia are intensifying. The prevention and controlling of myopia among children and adolescents should be strengthened, so as to reduce the occurance of myopia.

Correlation Analysis of the Change Law of Index Gas and Active Functional Groups in the Process of High-Temperature Spontaneous Combustion of Minerals in the Fushun West Mine.

The spontaneous combustion of underground minerals causes huge property losses and ecological damage. Coal and oil shale are co-associated minerals in the Fushun West Mine, and both have the ability to undergo oxidative spontaneous combustion. To study the effect of microstructure changes on the macroscopic gas product concentration during the mineral oxidation spontaneous combustion process in the Fushun West Mine, this study used a high-temperature temperature-programmed test to obtain the change trend of gas product concentration in different oxidation stages of minerals. Using Fourier transform infrared spectroscopy technology, the changes in active functional groups of surface molecules during the process of mineral oxidation and spontaneous combustion were identified. Finally, using the gray correlation degree, correlation analysis between the concentration of gas products and the concentration of active functional groups in different oxidation stages was carried out. The key reactive functional groups affecting mineral spontaneous combustion were identified. The essential reason for the change in the gas product was revealed.

COVID-19 and Tuberculosis Coinfection: An Overview of Case Reports/Case Series and Meta-Analysis.

Background: Coronavirus disease 2019 (COVID-19) and tuberculosis (TB) are two major infectious diseases posing significant public health threats, and their coinfection (aptly abbreviated COVID-TB) makes the situation worse. This study aimed to investigate the clinical features and prognosis of COVID-TB cases. Methods: The PubMed, Embase, Cochrane, CNKI, and Wanfang databases were searched for relevant studies published through December 18, 2020. An overview of COVID-TB case reports/case series was prepared that described their clinical characteristics and differences between survivors and deceased patients. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for death or severe COVID-19 were calculated. The quality of outcomes was assessed using GRADEpro. Results: Thirty-six studies were included. Of 89 COVID-TB patients, 19 (23.46%) died, and 72 (80.90%) were male. The median age of non-survivors (53.95 ± 19.78 years) was greater than that of survivors (37.76 ± 15.54 years) (p < 0.001). Non-survivors were more likely to have hypertension (47.06 vs. 17.95%) or symptoms of dyspnea (72.73% vs. 30%) or bilateral lesions (73.68 vs. 47.14%), infiltrates (57.89 vs. 24.29%), tree in bud (10.53% vs. 0%), or a higher leucocyte count (12.9 [10.5-16.73] vs. 8.015 [4.8-8.97] × 109/L) than survivors (p < 0.05). In terms of treatment, 88.52% received anti-TB therapy, 50.82% received antibiotics, 22.95% received antiviral therapy, 26.23% received hydroxychloroquine, and 11.48% received corticosteroids. The pooled ORs of death or severe disease in the COVID-TB group and the non-TB group were 2.21 (95% CI: 1.80, 2.70) and 2.77 (95% CI: 1.33, 5.74) (P < 0.01), respectively. Conclusion: In summary, there appear to be some predictors of worse prognosis among COVID-TB cases. A moderate level of evidence suggests that COVID-TB patients are more likely to suffer severe disease or death than COVID-19 patients. Finally, routine screening for TB may be recommended among suspected or confirmed cases of COVID-19 in countries with high TB burden.

Geomagnetic field absence reduces adult body weight of a migratory insect by disrupting feeding behavior and appetite regulation.

The geomagnetic field (GMF) is well documented for its essential role as a cue used in animal orientation or navigation. Recent evidence indicates that the absence of GMF (mimicked by the near-zero magnetic field, NZMF) can trigger stress-like responses such as reduced body weight, as we have previously shown in the brown planthopper, Nilaparvata lugens. In this study, we found that consistent with the significantly decreased body weight of newly emerged female (-14.67%) and male (-13.17%) adult N. lugens, the duration of the phloem ingestion feeding waveform was significantly reduced by 32.02% in 5th instar nymphs reared under the NZMF versus GMF. Interestingly, 5th instar nymphs that exhibited reduced feeding had significantly higher glucose levels (+16.98% and +20.05%; 24 h and 48 h after molting), which are associated with food aversion, and expression patterns of their appetite-related neuropeptide genes (neuropeptide F, down-regulated overall; short neuropeptide F, down-regulated overall; adipokinetic hormone, up-regulated overall; and adipokinetic hormone receptor, down-regulated overall) were also altered under the absence of GMF in a manner consistent with diminishing appetite. Moreover, the expressions of the potential magnetosensor cryptochromes (Crys) were found significantly altered under the absence of GMF, indicating the likely upstream signaling of the Cry-mediated magnetoreception mechanisms. These findings support the hypothesis that strong changes in GMF intensity can reduce adult body weight through affecting insect feeding behavior and underlying regulatory processes including appetite regulation. Our results highlight that GMF could be necessary for the maintenance of energy homeostasis in insects.

lncRNA ADAMTS9-AS2 Controls Human Mesenchymal Stem Cell Chondrogenic Differentiation and Functions as a ceRNA.

Long noncoding RNAs (lncRNAs) have emerged as key regulators of cell differentiation and development. However, potential roles for lncRNAs in chondrogenic differentiation have remained poorly understood. Here we identify lncRNA ADAMTS9 antisense RNA 2, ADAMTS9-AS2, which controls the chondrogenic differentiation by acting as a competing endogenous RNA (ceRNA) in human mesenchymal stem cells (hMSCs). We screen out ADAMTS9-AS2 of undifferentiated and differentiated cells during chondrogenic differentiation by microarrays. Suppression or overexpression of lncRNA ADAMTS9-AS2 correlates with inhibition and promotion of hMSC chondrogenic differentiation, respectively. We find that ADAMTS9-AS2 can sponge miR-942-5p to regulate the expression of Scrg1, a transcription factor promoting chondrogenic gene expression. Finally, we confirm the function of ADAMTS9-AS2 to cartilage repair in the absence of transforming growth factor ß (TGF-ß) in vivo. In conclusion, ADAMTS9-AS2 plays an important role in chondrogenic differentiation as a ceRNA, so that it can be regarded as a therapy target for cartilage repair.

Synthetic poly(vinyl alcohol)-chitosan as a new type of highly efficient hemostatic sponge with blood-triggered swelling and high biocompatibility.

Rapid and effective hemostasis for a noncompressible hemorrhage is the key to control bleeding and reduce mortality. Chitosan (CS) has been widely used as a popular hemostatic dressing; however, irregularly shaped wounds present in emergencies limit the performance of CS powder. To improve the hemostatic effect of CS, we modified it with poly(vinyl alcohol) (PVA), a fast-swelling sponge triggered by water. The novel synthetic PVA-CS was prepared by cross-linking PVA and CS during foaming and crosslinking reactions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction were utilized to analyze the characteristics of PVA-CS. In vitro, the swelling ratio and blood clotting ability were evaluated in different groups with various weight ratios or degrees of deacetylation of the CS, and the cytocompatibility and cell attachment on the material were analyzed by human dermal fibroblast (HDF) cell testing. In vivo, the hemostatic effects were evaluated in Sprague-Dawley rats and Bama miniature pigs in a femoral artery hemorrhage model or gunshot wound experiment. PVA-CS presents robust mechanical strength, rapid water-triggered swelling and a fast absorption speed. As compared with gauze and PVA, which are widely used in first aid, PVA-CS sponges showed an improved blood clotting ability and increased blood cell and platelet adhesion and activation. The PVA-CS sponges also showed high biocompatibility in cell viability, cell proliferation and cell attachment bioassays. Furthermore, in vivo evaluation of the PVA-CS sponges revealed excellent hemostatic performance and enhanced wound healing with increased re-epithelialization and decreased granulation tissues. The results of this study strongly support the use of these composite sponges for noncompressible hemorrhage in acute trauma and ballistic injuries.

Comparative transcriptomes and reciprocal best hit analysis revealed potential pigment genes in two color forms of Tetranychus urticae.

Tetranychus urticae Koch is a worldwide agricultural pest. There are two color forms: red and green. The molecular mechanism underlying this color variation is unknown. To elucidate the mechanism, we characterized differentially expressed pigment pathway genes shared in the transcriptomes of these two forms using RNA sequencing and reciprocal best hit analysis. Differentially expressed pigment pathway genes were determined by qRT-PCR to confirm the accuracy of RNA-Seq. The transcriptomes revealed 963 differentially expressed genes (DEGs), of which 687 DEGs were higher in the green form. KEGG enrichment analysis revealed carotenoid biosynthesis genes in T. urticae. Reciprocal best hit analysis revealed 817 putative pigment pathway genes, 38 of which were differentially expressed and mainly classified into four categories: heme, melanin, ommochrome and rhodopsin. Phylogenetic analysis of homologous ommochrome genes showed that tetur09g01950 is closely related to Ok. This study revealed putative pigment pathway genes in the two forms of T. urticae, and might provide a new resource for understanding the mechanism of color variation.

Association between MTHFR A1298C polymorphism and male infertility: A meta-analysis.

There have been several epidemiological studies evaluating the potential association between the methylenetetrahydrofolate reductase (MTHFR) A1298C polymorphism and the risk of male infertility. However, the results obtained were inconsistent. Therefore, we performed a meta-analysis to further examine the association between the MTHFR A1298C polymorphism and male infertility. A comprehensive search was conducted to identify all eligible studies from the online literature databases published prior to January 15th, 2016. A total of 20 studies with 4293 cases and 4507 controls were included. An odds ratio (OR) and a 95% confidence interval (95% CI) were calculated to assess the strength of the association. A cumulative meta-analysis, sensitivity analysis and assessment of the publication bias were also performed in this study. The results showed that in the overall analysis, the association between the MTHFR A1298C polymorphism and male infertility was not significant. A stratified analysis by ethnicity revealed a significant increase in the risk of male infertility in the Asian population with the MTHFR A1298C polymorphism (especially in the heterozygote model: OR=1.20, 95% CI=1.01-1.44, P=0.994; the dominant model: OR=1.23, 95% CI=1.04-1.45, P=0.996; and the allele model: OR=1.20, 95% CI=1.04-1.39, P=0.985) but not in the Caucasian population. In the stratified analyses, no significant association was observed between the different types of male infertility. This meta-analysis suggests the MTHFR A1298C polymorphism may be a potential risk factor for male infertility, especially in the Asian population.

Association between MTHFR A1298C Polymorphism and Male Infertility: A Meta-analysis / 华中科技大学学报（医学）（英德文版）

There have been several epidemiological studies evaluating the potential association between the methylenetetrahydrofolate reductase (MTHFR) A1298C polymorphism and the risk of male infertility.However,the results obtained were inconsistent.Therefore,we performed a meta-analysis to further examine the association between the MTHFR A1298C polymorphism and male infertility.A comprehensive search was conducted to identify all eligible studies from the online literature databases published prior to January 15th,2016.A total of 20 studies with 4293 cases and 4507 controls were included.An odds ratio (OR) and a 95％ confidence interval (95％ CI) were calculated to assess the strength of the association.A cumulative meta-analysis,sensitivity analysis and assessment of the publication bias were also performed in this study.The results showed that in the overall analysis,the association between the MTHFR A1298C polymorphism and male infertility was not significant.A stratified analysis by ethnicity revealed a significant increase in the risk of male infertility in the Asian population with the MTHFR A1298C polymorphism (especially in the heterozygote model:OR=l.20,95％ CI=1.01-1.44,P=0.994;the dominant model:OR=1.23,95％ CI=1.04-1.45,P=0.996;and the allele model:OR=l.20,95％ CI=1.04-1.39,P=0.985) but not in the Caucasian population.In the stratified analyses,no significant association was observed between the different types of male infertility.This meta-analysis suggests the MTHFR A1298C polymorphism may be a potential risk factor for male infertility,especially in the Asian population.

[Protective effects and underlying mechanisms of Panax notoginseng saponins against SH-SY5Y cell apoptosis induced by 6-hydroxydopamine].

The aim of this study is to investigate the protective effects of Panax notoginseng saponins (PNS) against 6-hydroxydopamine(6-OHDA)-induced apoptosis in SH-SY5Y cells and the possible underlying mechanisms. Cell viability was examined by MTT assay. The levels of lactate dehydrogenase(LDH), reactive oxygen species (ROS), malondialdehyde (MDA) and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase(GSH-Px) were measured using the respective assay kits. Apoptosis was measured by TUNEL kit, JC-1 and ROS was measured by staining with fluorescent dyes. The activation of caspase-3 was measured with the caspase-3 assay kit. The expression of nuclear protein Nrf2 and HO-1 were determined by Western blot. PNS had significant protective effects against 6-OHDA-induced apoptosis in SH-SY5Y cells in a time- and dose-dependent manner. PNS could attenuate 6-OHDA-induced suppression of SOD, GAT, GSH-Px (P < 0.01). PNS reduced the level of LDH, decreased the levels of ROS, MDA and increased cell viability and the mitochondrial membrane potential (P < 0.01). PNS also inhibited DNA fragmentation, mitochondrial response and the activation of caspase-3 (P < 0.01). Moreover, PNS pretreatment increased the expression of the nuclear Nrf2 and up-regulate HO-1. The protective effects of PNS could be inhibited by HO-1 inhibitor SnPP. In conclusion, PNS has significant protective effects against 6-OHDA- induced apoptosis in SH-SY5Y cells. The possible mechanisms of PNS are due to PNS-mediated activation of Nrf2, up-regulation of HO-1 and inhibition of oxidative stress.

FOXD1 promotes breast cancer proliferation and chemotherapeutic drug resistance by targeting p27.

Forkhead transcription factors are essential for diverse processes in early embryonic development and organogenesis. As a member of the forkhead family, FOXD1 is required during kidney development and its inactivation results in failure of nephron progenitor cells. However, the role of FOXD1 in carcinogenesis and progression is still limited. Here, we reported that FOXD1 is a potential oncogene in breast cancer. We found that FOXD1 is up-regulated in breast cancer tissues. Depletion of FOXD1 expression decreases the ability of cell proliferation and chemoresistance in MDA-MB-231 cells, whereas overexpression of FOXD1 increases the ability of cell proliferation and chemoresistance in MCF-7 cells. Furthermore, we observed that FOXD1 induces G1 to S phase transition by targeting p27 expression. Our results suggest that FOXD1 may be a potential therapy target for patients with breast cancer.

The complete mitochondrial genomes of six species of Tetranychus provide insights into the phylogeny and evolution of spider mites.

Many spider mites belonging to the genus Tetranychus are of agronomical importance. With limited morphological characters, Tetranychus mites are usually identified by a combination of morphological characteristics and molecular diagnostics. To clarify their molecular evolution and phylogeny, the mitochondrial genomes of the green and red forms of Tetranychus urticae as well as T. kanzawai, T. ludeni, T. malaysiensis, T. phaselus, T. pueraricola were sequenced and compared. The seven mitochondrial genomes are typical circular molecules of about 13,000 bp encoding and they are composed of the complete set of 37 genes that are usually found in metazoans. The order of the mitochondrial (mt) genes is the same as that in the mt genomes of Panonychus citri and P. ulmi, but very different from that in other Acari. The J-strands of the mitochondrial genomes have high (∼ 84%) A+T contents, negative GC-skews and positive AT-skews. The nucleotide sequence of the cox1 gene, which is commonly used as a taxon barcode and molecular marker, is more highly conserved than the nucleotide sequences of other mitochondrial genes in these seven species. Most tRNA genes in the seven genomes lose the D-arm and/or the T-arm. The functions of these tRNAs need to be evaluated. The mitochondrial genome of T. malaysiensis differs from the other six genomes in having a slightly smaller genome size, a slight difference in codon usage, and a variable loop in place of the T-arm of some tRNAs by a variable loop. A phylogenic analysis shows that T. malaysiensis first split from other Tetranychus species and that the clade of the family Tetranychoidea occupies a basal position in the Trombidiformes. The mt genomes of the green and red forms of T. urticae have limited divergence and short evolutionary distance.

[Clinical value of cupping spot effect].

The cupping spot is considered as one kind of skin change due to cupping treatment. With literature regarding cupping spot, the influencing factors and value of cupping spot in clinical diagnosis and treatment were analyzed, which could make a further exploration on the action mechanism of cupping treatment. The literature showed that the formation of cupping spot was related with cupping temperature, pressure, cup-retaining time, cupping area, individual difference and health condition, etc; cupping spot had the ability to assist diagnosis, prevent disease, cure disease and evaluate clinical efficacy. Previous studies on cupping spot have already made some progress, and played a positive significance on finding cupping rule and studying its mechanism. However, the research for this area is still in the primary stage, which needed deeper study to reveal scientific connotations of cupping spot.

Influence of hyaluronic acid on wound healing using composite porcine acellular dermal matrix grafts and autologous skin in rabbits.

This study aims to explore the influence of hyaluronic acid (HA) on wound healing during xenogeneic porcine acellular dermal matrix (PADM) composite skin grafting. The results will facilitate the development of methods for improving graft contracture and poor elasticity of composite transplantation. Exogenous HA was added to composite PADM grafts and to thin autologous skin grafts during rabbit full-thickness skin wound repair. The influence of HA on wound healing was evaluated according to its contracture rate and its expression of collagen types I and III. The possible mechanism was then explored based on HA metabolism and vascularisation in the skin graft. The results show that exogenous HA relieves graft contracture on rabbit wound surfaces, increases collagen I and III expression and decreases the ratio between collagen types. HA stimulates the generation of more CD44 receptors to strengthen its enzymolysis. The resulting metabolites promote the vascularisation of the wound surface, which are conducive for mitigating graft contracture, and further improve the composite grafting effect.

[Effects of hyaluronic acid on biomechanic performance of porcine acellular dermal matrix plus thin skin autograft after transplantation].

OBJECTIVE: To explore the effects of hyaluronic acid (HA) on biomechanical properties for porcine acellular dermal matrix (PADM) plus thin skin autograft after transplantation. METHODS: The dorsa of 10 Japanese white rabbits were symmetrically divided into four areas of A-D by random grouping. Full-thickness skin defects were created in Groups A-C while Group D was blank with normal skin. Operations were performed in Group A: implant with HA + PADM + thin skin autografts, Group B: implant with PADM + thin skin autografts and Group C: skin autografts group. Histological examination of specimen was performed at Day 56 postoperatively. And the biomechanical properties such as relaxation and stress-strain properties of grafts were recorded. RESULTS: The structure of PADM was found to be basically intact by hematoxylin and eosin E dyeing in Groups A and B. In Group A, dense fiber structure could be observed. Lots of regularly arranged collagenous fibers and new blood capillaries were grown into the dermal matrix with sparsely distributed inflammatory cells. In Group B, acellular dermal matrix became clustered with a small amount of invaded fibroblasts. And there was a high expression of inflammatory cells. The biomechanic performances of transplanted skin were: Group A's curve was mostly close to that of Group D's, Group B's curve was the most further from that of Group D's (P = 0.001) and Group C's curve stayed between Groups A and B. Under the same strain, the stress of Groups A-D was (87 ± 8), (115 ± 9), (63 ± 7) and (81 ± 4) kPa respectively. No significant difference of stress existed between these two groups (P = 0.838). There was significant difference of stress between Groups B/C and D (P = 0.001 and P = 0.009). CONCLUSION: Topical hyaluronic acid may be used to enhance the biomechanics performances of transplanted skin.